I've been following the progress of the new Delta IV rocket and am surprised at the amount of technical problems Boeing have had with the vehicle.

Considering that it has been undergoing testing on the launch pad for over 6 months you would have thought that all of these teething troubles should have been ironed out.

Initially I thought that the 3 core booster design was a clever idea to increase the payload weight but now I'm not so sure. I'm wondering whether the vehicle is too complicated, it is effectively nearly the same as trying to launch 3 rockets simultaneously.

Considering that this is one of the boosters touted as a possible lift engine for a future CEV, I was wondering is it reliable enough or whether a booster with a single core would be better. If a CEV had to launch in a hurry to perform a rescue, the turn around time would probably be fairly slow.

Boeing have said that the Delta IV can be expanded to have 6 or 7 core boosters and I hate to think of the reliability problems that such a rocket might have. The fuelling of the vehicle is complicated enough without electronics failures as well. It is still early days and maybe these problems will work themselves out but I cant help thinking that a single booster would be much simpler and easier to operate.

_________________A journey of a thousand miles begins with a single step.

Ok. IANAAE, but my understanding is that the sole advantage of having strap-on-the-side boosters is just that if you want a heavier launcher, you can just strap on some more boosters! On the other hand, it seems like you BETTER have your gyros all synced up, lest all three motors start pushing in different directions. If one has a failure, forget it.
If I had to ride on a rocket, I think I'd put my trust in a monolithic type with engine-out reliability, like a Saturn V or a Falcon V.

If I'm wrong about any of these assumptions, please feel free to correct me.

I think that the Delta Heavy concept for really heavy payloads will not be usable, one of the restrictions will be the physical size of the payload. I believe the booster cores are 5m in diameter so even with a slightly bigger upper stage and fairing payloads will be limited to no more than a couple of meters wider than this.

Also the number of cores necessary to get really big loads (+50,000kg) into orbit will make the vehicle to complicated.

If you compare this concept to something like Robert Zubrin's Shuttle derived Ares launcher designed for his Mars direct strategy, Delta IV Heavy looks like a headache.
The proposed Ares vehicle can lift 121,000kg to ISS orbits, or 75,000kg without an upper stage. Its core booster has a diameter of 10m making much larger payloads possible, this would have an effect on the number of launches necessary to assemble space stations or Lunar/Mars missions in orbit.

In addition Ares uses a lot of the existing infrastructure and equipment used on the shuttle so should not take any longer to build than Delta. The use of Ares could also have the added advantage of doubling as an alternative to using orbiters to assemble the ISS and so save on the number of flights necessary (A shuttle without an orbiter attached can easily carry twice the payload). Use Ares to send large payloads, such as CEV, into orbit and a much smaller craft for ferrying crew.

_________________A journey of a thousand miles begins with a single step.

I agree, i don't see the point off this rocket, even if it should work. It will always be more cost effective to essamble something where it should be the first build it, assemble it at the factory and then ship it in total.

From the trouble i've read on space.com, it almost seems to me that they are just doing something, instead of contributing to the spacesector. No one will need this gian dollar-eating rocket. They should have made a simple rocket and upgrade it from there. Imo.

I cant see Boeing, or Lockheed for that matter, making a cheap rocket but I thought they might make a more simple rocket. It seems ludicrous to produce a complicated rocket then compound its complexity by duplicating more of the same core boosters in the one unit.

Can you imagine trying to run scheduled flights to one of Bigelows orbiting stations with something this complex? I think that we are getting close to the point where someone will have to design and build a real heavy lift rocket rather than strapping mutiple small ones together if NASA's vision is ever going to get off the drawing board and into orbit.

I dont think I would travel to one of Bigelows inflatables knowing I was going to launch on a Delta IV heavy configuration, I'd feel much safer on a rocket constructed from a single core even if it had solid boosters strapped to it.

I wonder if any of the original Saturn Vs would still fly

_________________A journey of a thousand miles begins with a single step.

Not after collecting rust and pigeon dropping for 30 years. And the technical plans and manufacturing jigs were deliberately destroyed by NASA to make the Shuttle the only choice.

The Shuttle is the ultimate example of "designed by a committee".

For example:
They wanted to use an American developed LH2/O2 engine instead of a Von Braun derived RP/LOX as on the Saturn first stage. So the low density fuel requires a massive tank that is too big for the orbiter, so it has to be external & disposable.

They want to claim they re-use the SME's, so they have to attach them to the orbiter, (instead of the tank), which then has to hang on the side of the huge tank, instead of on top, which makes the thrust vector off centre, and it changes as the centre of gravity changes as the fuel tank empties. Oh, and the orbiter has to be a lot bigger and heavier, because it has to carry those 3 engines everywhere.

If they had even just put the engines on the bottom of the tank and thrown them away, the shuttle would be smaller & lighter and have less heating issues on re-entry, and probably not need those ridiculous tiles. Which can only get damaged on launch because the orbiter is hanging on the side instead of sitting safely on top!

It cost a ridiculous amount of money to fly each mission, and has to be practically rebuilt each time. Why on Earth would you want to adapt that technology?

Delta IV may be a bit dodgey, but there are a lot of other new launchers being developed out there that make more sense.

The shuttle isnt all bad and the Ares design I mentioned uses the best bits from it, the side load problems do not exist as the payload is mounted directly above the tank. The tank itself has SSMEs fitted directly to it making it a booster in its own right and the SRBs have flown over a hundred times without incident since the O-ring problem was fixed. Why throw these things away when they work OK? Most of the problems are directly associated with the orbiter and I would agree that the best place for it is in the nearest museum.

What I was advocating was the use of equipment and facilities already in existence to create a heavy booster rather than strapping small ones together which appears to create problems. Given that most of the hardware on an Ares is already made it should be quicker to develope than a new booster.

_________________A journey of a thousand miles begins with a single step.

The shuttle isnt all bad and the Ares design I mentioned uses the best bits from it, the side load problems do not exist as the payload is mounted directly above the tank. The tank itself has SSMEs fitted directly to it ...

All the shuttle derived booster proposals, I've seen, stiil have the SSME's mounted off centre, and all the cargo pods in the orbiter position. Given the height of the External Tank, current infrastructure wouldn't allow mounting anything on top, and putting SSME's underneath would just increase that height and require mounting changes to the SRB's.

Speaking of SRB's, they are another example of shuttle insanity. I've heard there was an alternate vendor, just down the road from KSC, who could have produced them in one piece. But the successful vendor was a little cheaper, but on the other side of the country, so they had to ship them in pieces to be assembled, hence the O rings. Oh, and they are barely re-usable, have to be fished out of the sea, un-throttleable, environmentally unfriendly, need I go on?

I'm trying to work out what is good about the shuttle, but having a bit of trouble. A widely held view is that the shuttle program has held up space development for 25 years.

Hang on, I've thought of something. The shuttle has a pretty good OMS/RCS system, apart from being incredibly toxic of course.

I think that the policy of throw everything away and start from scratch everytime has slowed progress and cost billions of extra dollars. You point out the folly of tossing everything concerning Saturn V in the dustbin but say do the same for the shuttle.

Granted the shuttle has not been good for the space program and has probably held it back but using it as a heavy lift vehicle for equipment without the orbiter is probably cheaper and less likely to go wrong than a Delta IV with 7 common core boosters strapped together.

I would favour a single core large lift booster (50,000kg+), but none exist and the time necessary to build one will be longer than the shuttle approach. Modifying existing infrastructure to accomodate a shuttle derived launch vehicle will be faster and less expensive than building new for a new booster.

In addition all the shuttle facities will be operational until the end of the decade at least, probably longer, creation of a new booster facility now will mean another set of infrastructure built alongside or at different locations, splitting effort and finance between the two programs and possibly slowing both. Waiting until after the shuttle finishes service could mean the middle of the next decade before a booster appears.

The real question is whether there will be enough heavy payloads to put into orbit, NASA has not yet said how many launches it will need or what the payload weights are. Lockhead or Boeing will not do to much until this is known, a lot of small payload launches to assemble something in orbit would allow them to make a bigger profit easier with existing hardware.

The SRBs do not need to be throttlable, I dont see why that is a problem. Just because you dont like the history associated with equipment procurement or some of the stupid things done in the past that should not preclude you from using what you have.

The original thread was about using Delta IV for a future manned craft launch. Would NASA use Arianne V as a booster (the latest version will launch ESA's ATV to the ISS), could the same vehicle be used for manned craft. This could form part of the coopertion the US wants with other agencies and be a cheaper option for a booster as all facilities exist for this vehicle. The US would have the orbiters in the short term as a homegrown launch system (no matter how flawed) and allow NASA to concentrate on the manned vehicle itself. This might also stop the Russians from jacking Soyuz prices up if an alternative exists should the US have another set back to their manned programme.

_________________A journey of a thousand miles begins with a single step.

It seems that after all the problems the rocket went up without a hitch and I must admit it was pretty awesome. One of the things said during the webcast was that the payload could be doubled by the addition of 6 solid rockets (2 on each core booster) and a few modifications to the upper stages. This starts to make it look like a more promising heavy lift vehicle, if it can boost 20-25 tons to orbit with only the 3 coomon core boosters then this is much less logistically complicated than fuelling 6 or 7 boosters.

The new Russian Kliper concept is 13,000kg so a US ship of similar size or a little bigger would only require a 3 core rocket.

Even though I thought the launch was pretty impressive I still think a large single core booster would be much easier to use as a launch vehicle for a manned craft. I cant understand why the Titan rocket is being retired next year to make way for this beast.

_________________A journey of a thousand miles begins with a single step.

I think that the policy of throw everything away and start from scratch everytime has slowed progress and cost billions of extra dollars. You point out the folly of tossing everything concerning Saturn V in the dustbin but say do the same for the shuttle.

The problem with the shuttle, is that the basic design is flawed. Keeping it going in any form, costs far too much. Saturn V was 1960's technology that could have been developed and improved while still flying regularly. I believe NASA should not have any booster program. They should just buy launch services from a free market.

Andy Hill wrote:

The SRBs do not need to be throttlable, I dont see why that is a problem. Just because you dont like the history associated with equipment procurement or some of the stupid things done in the past that should not preclude you from using what you have.

Because the SRB's are not throttleable, the shuttle accelerates too quickly and runs into max Q (aerodynamic load) problems. Also they cannot be switched off once started, which makes it very tricky to abort for the first 2 minutes after launch.

Looks like the SSME's are in a conical fairing on the side, not underneath. Otherwise you would have to re-plumb the tank. And they have to design a new 2nd stage ,and increase the height of the launch pad gantry, and the vehicle assembly building. Could an existing shuttle still use these modified facilities?

While I'm a firm believer in KISS (no, not the rock band - keep it simple, stupid) the delta IV does have a major advantage in its scalablilty and flexibility. For one thing, you increase your unit quantity of manufacture, which makes it cheaper and allows you to ride down the experience curve quicker. From an flexibility standpoint, you could keep a couple on hand and rapidly configure the launch vehicle to match the payload by adding and/or subtracting boosters. And then if the market for heavy payloads fails to materialize, you can still have the possibilty to get a payback by using the same components to go after smaller payloads. Contrast this to the much larger and riskier development costs to put together a monolithic heavy vehicle with an uncertain future.

So while I expect that initially the launch times will be slower, the Delta IV launch team will more quickly gain experience troubleshooting and fixing design flaws because each launch is the equivalent of sending up (in this case) three rockets. It is a gamble, but in this first launch, it appears that they're getting over the hump and the program could be successful.

The questions remains if they will be able to improve the rockets quick enough to overcome the inherent reliability issues of the more complex system.

The Delta iV design is all about the economics. Of course, one could make a the same argument for Aries. However, you've got to keep all those aerospace engineers employed somehow, which is why we keep getting clean paper designs which only offer incremental technology improvements. As long as it's all about the time and materials, real innovation isn't going to happen because that entails taking risks instead of chilling out and spending the people's dime to build a ho-hum product. That's why it's clear to me that the future of space rests with the private sector, not government projects.

The problem with the shuttle, is that the basic design is flawed. Keeping it going in any form, costs far too much. Saturn V was 1960's technology that could have been developed and improved while still flying regularly. I believe NASA should not have any booster program. They should just buy launch services from a free market.

Most heavy launch vehicles are a similar design, a common core booster with solid rockets bolted to the side that cant be thottled. The amount of thrust is varied by throttling the booster engine, if the SRBs produce to much thrust then their propellant can be altered to burn slower and longer. Agreed NASA should just buy launch services from the free market but because they buy single launches they never get a discounted price, if they bought 10 or even 20 launches at a time from a single supplier they would get a huge discount but other suppliers of large launchers would probably stop supplying heavy vehicles.

WannabeSpaceCadet wrote:

Looks like the SSME's are in a conical fairing on the side, not underneath. Otherwise you would have to re-plumb the tank.

This should not be a problem. A while back the Space Island Group wanted to use the external tanks to construct orbiting stations and they wrote to Lockheed asking whether they could be modified to fly without an orbiter attached and the SMMEs mounted underneath. Lockheed wrote back saying that this would be possible with only minor changes to the design.

WannabeSpaceCadet wrote:

And they have to design a new 2nd stage ,and increase the height of the launch pad gantry, and the vehicle assembly building. Could an existing shuttle still use these modified facilities?

.

Designing a single stage will be easier than an entire vehicle and with the amount of data already amassed on how the shuttle performs the task should be easier still. It should not be a problem to alter the gantry to be dual use both concepts share many features but even if a different gantry is required there are a lot of launch pads that could be modified. Making the assembly building taller should not impact on the shuttle.

_________________A journey of a thousand miles begins with a single step.

May be Boeing one day will find themselves forced to do service for private space missions because of the heavy payload market failing to "materialize". To launch hundreds or thousands of nano-satellites at once may be a good thing if that market would grow to amounts SpaceX's Falcons cannot serve completely. May be that Boeing is going to be forced to launch private manned orbital vehicles . If so the will find themselves in situation simmilar to IBM's former situation at the PC market...

May be Boeing one day will find themselves forced to do service for private space missions .... May be that Boeing is going to be forced to launch private manned orbital vehicles . If so the will find themselves in situation simmilar to IBM's former situation at the PC market...